The passing of a man at the Burning Man celebration in the US territory of Nevada is being treated as suspicious, specialists state.Shane Billingham, 33, was found unresponsive in his car at around 18:30 local time (00:30 GMT) on Thursday.
Mr Billingham, a New Zealand national, had “poisonous” levels of carbon monoxide in his blood, police said.
Bystanders reportedly attempted CPR on Mr Billingham before paramedics arrived.
He was taken to a medical tent, where he was later pronounced dead.
Pershing County Sheriff’s Office said it was investigating the death as suspicious.
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A post-mortem examination found Mr Billingham had “a concentration of carbon monoxide in his blood which would be considered poisonous to human life”.
“Preliminary toxicology showed the presence of controlled substances to be an exacerbating factor,” the Washoe County medical examiner’s office said.
A makeshift memorial for Mr Billingham has been set up at Beats Boutique, the camp where he was staying at the festival.